From prior patents, including commonly assigned U.S. Pat. Nos. 4,928,729; 4,991,556; 5,002,030; and 5,076,320; it is known to mount a fuel pressure regulator on a fuel rail assembly for the purpose of regulating the pressure of the fuel that is supplied to fuel injectors mounted on the fuel rail. The pressurized fuel that is delivered to the fuel rail is pumped from a fuel tank through a fuel supply conduit, and excess fuel is returned from the fuel pressure regulator's return port through a fuel return conduit to the tank. This type of system is sometimes called a return type system. A typical fuel pressure regulator used in such a system comprises a housing having a movable wall that divides the housing into a fuel chamber and a control, or reference, chamber. The reference chamber's interior is referenced to engine intake manifold vacuum so that the regulated pressure across the fuel injectors is essentially insensitive to changes in manifold vacuum.
Another type of fuel injection system does not have a fuel return conduit and is sometimes called a non-return, returnless, or dead-headed system. In such a system, the fuel pressure is regulated at the tank, with the fuel pressure regulator being part of a pump module that is assembled into the tank and contains, inter alia, a fuel pump. If a fuel pressure regulator like the one in the above-described return system were to be used in a non-return system, a vacuum conduit from the engine intake manifold would have to be connected to its reference chamber if vacuum compensation were to be retained in the same way, and the fuel pressure regulator would simply spill excess fuel into the tank through its return port. On the other hand, if the reference chamber were exposed to the headspace of the tank, either intake manifold vacuum compensation would not be used or else it would have to be provided in some other way.
The present invention relates in one respect to an improvement in a fuel pressure regulator for a non-return system, and in another respect to an improvement in the mounting of such a fuel pressure regulator. The invention arises through the recognition that certain features of the prior fuel pressure regulator used in a return type system are unnecessary when used in a non-return system. As a result, the invention provides a novel and unique configuration for a non-return type fuel pressure regulator that uses fewer parts than its return type predecessor, and is therefore more cost-effective than simply moving the prior regulator into the tank. Several embodiments of the inventive fuel pressure regulator are disclosed.
The foregoing, along with other features, advantages, and benefits of the invention may be garnered from the ensuing detailed description of a presently preferred embodiment of the invention. Drawings accompany this disclosure and illustrate the best mode contemplated at this time for carrying out the invention.